ucert: work around short read

usign occasionally writes 16 characters then exits without writing a LF,
leaving ucert hanging waiting for more input.  Accept 16 characters
or more rather than 17 to work around the short read.

Signed-off-by: Mike McCormack <mike@atratus.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

package/system/ucert/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/ucert.git
-PKG_SOURCE_DATE:=2018-08-08
-PKG_SOURCE_VERSION:=1056e730f56adbc6bc77872e2bbd2bbe01512ec9
-PKG_MIRROR_HASH:=59fc4ab5b5cb10c6e9e0899e3ed5de2f57926e980d31c13ddd1662f36cf40cef
+PKG_SOURCE_DATE:=2018-09-18
+PKG_SOURCE_VERSION:=e1c722b1b6cbf2527b3178342464e56b97825874
+PKG_MIRROR_HASH:=36dcca7c2d649a6c34a8daaaef4698fbeb808fd6580c6bfb1ca35f4f06825d17
 
 CMAKE_INSTALL:=1
 PKG_CHECK_FORMAT_SECURITY:=1